This invention relates generally to safety devices for hollow bore medical needles and particularly to syringe needle devices which employ protective needle shields or sheaths for securely shielding sharp needle tips, both before and after being used in a medical procedure. This invention more particularly relates to removable medical needle shields, sheaths or shrouds which may be used as removable and replaceable protective needle covers. Consistent with such uses, the medical needle may be accessed, covered and reaccessed repeatedly for such purposes as protecting a sharpened needle tip in transit before use, ad interim after a preliminary use, such as filling a syringe with a medication, and being displaced to a safety, needle-covering position after a medical procedure is completed.
Problems associated with inadvertent needle sticks are well known in the art of blood sampling, percutaneous medication injection and other medical procedures involving use of medical needles. Ever increasing attention is being paid to needle stick problems due to the contemporary sensitivity of exposure to AIDS, Hepatitis and other serious blood-borne diseases.
Commonly, procedures involving removing a needle from a patient require a technician to use one hand to place pressure at the wound site where the needle is being withdrawn while removing the needle apparatus with the other hand. It is common practice for a tending technician to give higher priority to care for the wound than is given to disposal of a needle. In the case of commonly used, non-safety devices such priority either requires convenience of an available sharps container within ready reach or another means for safe disposal without leaving the patient""s side. Providing adequate care, with accompanying safety procedures, is often compounded by patient physical condition and mental state (e.g. in burn units and psychiatric wards). Under such conditions, it is often difficult, if not impossible, to take appropriate action to properly dispose of a used, exposed needle while caring for a patient. Further, common practice of filling syringes with medication in one area and then transporting an uncapped needle (recapping a needle is currently discouraged in U.S. medical practice due to dangers associated with recapping) to a patient area provides a significant opportunity for accidental needle sticks.
Widespread knowledge and history associated with needle care and disposal problems have resulted in conception and disclosure of a large number of devices each of which represents an attempt to provide not only a solution to the problem of needle sticks, but also a device which is commercially viable (i.e. cost and price competitive with currently used non-safety devices). In the case of syringes, current devices which are used to shield syringe needles often require two hands and, in some devices, safety status of needle shields are not readily apparent.
Examples of disclosures of safety devices which protect needles by moving a protective shield over a sharp end of a syringe or other hollow bore medical needle are found in U.S. Pat. No. 5,823,997 issued Nov. 17, 1998 to David L. Thorne (Thorne), U.S. Pat. No. 5,348,544, issued Sep. 20, 1994 to Sweeney et al. (Sweeney), U.S. Pat. No. 5,246,428 issued Sep. 21, 1993 to Donald W. Falknor (Falknor), U.S. Pat. No. 5,256,153 issued Oct. 26, 1993 to Lawrence W. Hake (Hake) and U.S. Pat. Nos. 5,139,489 and 5,154,285, issued Aug. 18, 1992 and Oct. 13, 1992, respectively, to William H. Hollister (Hollister). There are many other examples of safety devices which retract needles into housings, however, this instant invention is more directly related to devices which extend a shield over a needle rather than to those which employ needle retraction.
Thorne discloses a safety needle enclosure which is disposed to rotate about a needle and, upon being displaced to a needle shielding state, forms a substantially rigid part in cooperation with the needle to thereby provide a safety needle shield. The enclosure comprises a plurality of rigid segments serially interconnected by a plurality of intersegment hinges, which are preferably living hinges. The segments are disposed about a medical needle, folded upon each other during the medical procedure and extended, only at the end of the procedure, to form a secure, substantially rigid, single-use safety shroud. During the procedure, the enclosure is folded and conveniently disposed about a proximal portion of the needle. At the end of the procedure, the enclosure is extended to protectively sheath and secure the needle in a substantially rigid structure formed by the combination of the enclosure and the needle.
Sweeney discloses a device comprising a guard which is manually, slidably movable along a needle cannula from a site proximal to a user to a distal site where the needle tip is shielded. The device comprises a hinged arm which extends along the needle cannula and which is moved distally to collapse upon itself to extend the shield over the tip. Access to the tip is denied by a metallic clip. An alternative embodiment is also disclosed by which the manual operation is augmented by a spring. A device based upon Sweeney is currently being distributed by Becton Dickinson and Company, Franklin Lakes, N.J. in which three separate parts (two injection molded and one metal clip) are used to mechanize the guard. Once the device is extended to shield a needle tip, it should not be reset to recover use of the needle for a subsequent procedure, and is therefore, like the device taught by Thorne, a single-use device. Also, the hinged arm requires activation in the region of the needle itself and comprises parts which are of a size which occasionally impedes a user""s line of sight to insertion locations.
Falkner, and related disclosures, disclose devices comprising shields which are automatically releasible to extend distally from a user to cover a needle. The devices comprise latch mechanisms which are manually switched between unlatched and latched positions to free the needle for use and lock the shield over the needle, respectively. Of course, position of the latch mechanism provides a visual interpretation of the safety of the device (i.e. whether or not a latch is engaged), but that is the only safety mechanism and a xe2x80x9cmissedxe2x80x9d indicator of latch mechanism position may be possible in stressful circumstances. When the latch mechanism is in the unlatched position, access to the needle is not only possible, but likely when the front of the device is impacted by a body part. In addition, the shield, though made of transparent material, covers a portion of an attached syringe body until fully extended and may make accurate reading of portions of volume measurement indicia on the syringe body difficult when the syringe is being used in a titrating application.
Hake is representative of disclosure of devices comprising a manually slidable guard which is disposed over a syringe body during a medical procedure involving a medical syringe needle and manually, slidably moved distally into a needle guarding position usually at the end of the procedure. Commonly users of such devices complain of difficulty of seeing measurement indicia while the guard is disposed over the syringe body and of danger of inadvertent needle sticks while sliding the guard distally to cover the needle. As well, it is generally difficult to determine whether a guard is in a locked or unlocked state when it covers the needle, making an additional possibility of inadvertent needle sticks.
Hollister discloses a needle protection device which may be used with a double-ended needle assembly or with a simpler single needle system. The protection device comprises a substantially rigid housing flexibly connected to a container (for a vacuum tube sampling system) or to a needle hub. To exercise the protection device, the rigid member is pivotally rotated into engagement with an exposed needle of the double-ended needle assembly and is securely affixed to the exposed needle. A major drawback of the needle protection device of Hollister is the size and position of the rigid housing. During use of an assembly or system in a medical procedure, length and position of the housing member is considered by some to be inconvenient. A second drawback is the apparent requirement either for two handed operation to pivot the housing to engage the needle or for the requirement to find and use a stable support surface against which the housing is pressed while the needle is swung into engagement with the housing. In a currently marketed format, an integral container holder version of the device disclosed by Hollister comprises two injection molded parts which permit the housing to be rotated, as much as possible, out of the way during a medical procedure. Such a format requires five injection molded parts, including a disposable needle assembly.
An often occurring circumstance, especially in the use of syringe needles, involves a need to use a needle a plurality of times. As an example, when an intramuscular injection is made, it is common practice to draw contents from a drug vial into a syringe and then inject the contents into a patient. It is desirable to use the same needle for penetrating a membrane on the drug vial and then for injecting the patient. However, the site where contents are drawn from the drug vial may be some distance form a site where the patient is to be injected. Such situations may result in a technician""s recapping the needle (a procedure which is currently discouraged and against standard precautions) for transport to the patient. Equally as concerning is another practice of carrying the needle unprotected. Some currently available safety devices, such as those based upon Hake, permit covering and reaccessing a needle; however, other factors, such as those disclosed above have limited acceptance of these safety devices.
Generally, other than acceptance of the type of operation offered by such devices, commercial viability is dependent upon manufacturing cost. Purchase decisions in the area in which these devices are used are very cost sensitive. If gains in either improvement in safety or in labor savings are not found to make a device sufficiently competitive with contemporary items currently on the market, those devices are usually not found to be commercially viable.
In brief summary, the novel invention disclosed herein dramatically diminishes known major problems resulting from injury-related needle sticks which occur when needle tips are bared as medical needles are withdrawn from a patient at the end of a needle insertion procedure, but, perhaps more important to general patient welfare, these inventions provide opportunity for fabrication of a very low cost safety needle system which permits access to a medical needle in several steps in medical procedure, while being able to return the needle to the safety of a covering enclosure between the steps.
Basic to the invention is a medical needle device which employs a protective needle shield which may be somewhat similar in form and function to a sheath disclosed in Thorne, but is discernably different in that the shield of the present invention is displaceable to cover and protect a needle tip and which is further displaceable to bare the needle and tip a plurality of times for use throughout a medical procedure. It is further differentially discernable because the needle tip is untouched by the shield in addition to being protectively covered.
For reference, Thorne discloses a foldable needle sheath which is articulated to fold about a medical needle to permit access to the needle in a medical procedure. The sheath is hingeably attached to a structure (e.g. a needle hub or phlebotomy barrel) at a point away from a sharpened needle tip which is later enclosed to protect a user. At the end of the procedure, the sheath is unfolded and extended away from the structure in the direction of the needle tip to encase and thereby protect users from contact with the needle and its tip. To permit the sheath to unfold about the needle, each folded part of the sheath is serially constructed of a plurality of rigid and interconnected segments. At least one segment comprises an orifice through which the needle passes and about which each at least one segment rotates while the sheath is being extended. Each segment is connected to at least one other segment by a hinge, which is preferably a molded, living hinge, and comprises a channel into which the needle is nested when the sheath is fully extended. The sheath comprises a catch which securely affixes the sheath when the needle is captured to be disposed in the sheath. Once the sheath is extended and the needle so captured, the combination of sheath and needle form a substantially rigid member which shrouds the needle and its sharpened tip to provide safety from dangerous contact with the tip and needle. All hingeable attachments are preferably living hinges integrally and concurrently formed with other sheath parts. It is very important to note that, once the sheath of Thorne is extended to protect the needle and its tip, Thorne teaches of no subsequent release of the sheath from being disposed to protect the needle and tip.
In the present invention, a shield is disposed about a needle and tip to provide protection. However, different from the teachings of Thorne, a temporary, releasible latch is provided which may be disengaged to permit the shield to refold and, thereby, permit reaccess to the needle for a subsequent medical procedure. Once each procedure is complete, the shield is again extended and latched to provide a safety cover. Further, a selectively activated unreleasible lock is provided for the protective shield to thereby assure secured needle tip protection at the end of use.
In a preferred embodiment, the shield includes a needle guide, proximally disposed relative to the tip of a needle, which protects the tip from damage through contact with the shield, both, as the protective shield is displaced to cover and shield the needle and as the shield is removed to bare the needle for use. The needle guide is disposed and constrained to travel in alignment with the long axis of the needle and also constrained to facilitate movement of the shield about the needle without contact with the needle tip.
Generally, the device may be configured into at least two temporary or releasible but stable states. In one stable state the shield is constrained to be disposed xe2x80x9cout-of-the-wayxe2x80x9d when the needle is bared for use. In a second releasible stable state, the shield is constrained to be protectively disposed about the needle and needle tip. Further, the device and shield, in combination, include the permanent lock which is securely and unreleasibly affixed to prevent further use of the device when use is complete. Preferably, latches are used to constrain the shield in each of the stable states.
Other important factors in safety needle devices involve whether the device can be effectively used by a single hand and the number of times a needle may be accessed while being maintained in a needle-safe condition between uses. Especially in the case of hypodermic syringe needle devices, ability to access a medical needle from a safety state a plurality of time is very important as it is common practice to prefill a syringe using a needle to access a medical fluid containing vial and then deliver the contents of the syringe to a patient using the same needle.
Generally, the invention provides for single handed operation and for access to a medical needle a plurality of times while protecting a user from inadvertent injury from the needle while protecting the needle and especially its fragile tip from damage when the device is moved to, displaced from or simply disposed within the safety of the shield.
Accordingly, it is a primary object to provide a device having a safety shield for a medical needle and an associated sharpened tip which permits, within desirable and acceptable bounds of safety and efficacy, a plurality of cycles of shielding and baring the medical needle whereby the needle may be covered or otherwise shielded for transport or other non-needle use functions and then safely bared for use more than one time.
It is an important object to provide a medical needle shield which is securely but releasibly affixed to cover and protect the medical needle and its associated sharpened tip in a first state.
It is another important object to provide a medical needle shield which is securely and unreleasibly affixed to cover and protect the medical needle and sharpened tip in a second state.
It is yet another important object to provide a needle guide which is disposed to operate within the shield to assure the sharp tip of the needle is untouched throughout each needle covering and baring procedure.
It is a particularly important object to provide a shield which is folded out-of-the-way in one state whereby a medical needle may be used in a medical procedure and which is unfolded to combine with the medical needle to form a substantially rigid needle shrouding structure which protects against inadvertent contact with a sharpened tip of the needle.
It is a very important object to provide a releasible and lockable needle shield which is both releasible from a needle protective state whereat the needle tip is protectively covered and thereafter displaced to a locked state in which the shield is securely affixed in an extended state to unreleasibly protect the needle tip.
It is also a very important object to provide a needle shielding device which is facilely operable by a single hand.
These and other objects and features of the present invention will be apparent from the detailed description taken with reference to accompanying drawings.